Abstract：Oblique-layered rocky landslide under lockup with combination of flank and bedding plane is a new type of deformation and failure of slopes. For the oblique slopes of layered rocks，the dips of layered rocks and slope intersect each other，the angle between the strike of layered rocks and the strike of slope is more than thirty degrees，and the dip angle of the layered rocks is greater than ten degrees. Generally the progressive failure is developed of oblique-layered rocks at the pre-failure stage. In plane，one of flanks is free due to the preexisting fault and subsequent erosion by water，and another flank on the middle part of the deformed layered rocks is connected with undisturbed rocks. In addition，the oblique-layered rocks spin asymmetrically around an axis perpendicular to the potential slip surface near the middle locked segment of the flank. On cross-section，along the potential slip surface，the deformed layered rocks are not completely sheared through the surface，and the downslope movement in the layered rocks decreases gradually from outside to inside where sliding is impeded. So according to the behavior of the layered rocks，pre-failure deformation of landslide can be described by bending of multilayered rectangular plates with two adjacent edges fixed and the other free under combined transverse and lateral loads，and the onset of failure of landslide can be viewed as buckling-bending and critical rupture of the plates. By means of Rayleigh-Ritz energy methods，an equation of elastic deflection-load of plate is established，and then the ultimate bearing capacity of plate is determined with the approach of plastic limit analysis. Consequently，a stability criterion of landslide is deduced and a case is analyzed，which is proved to be effective in the quantitative stability evaluation of this kind of landslide.
